(i) Field of the Invention
The present invention relates to a method for producing a soft magnetic hexagonal ferrite sintered material and to a soft magnetic hexagonal ferrite sintered material produced by the method.
(ii) Description of the Related Art
Conventional techniques to produce a hexagonal ferrite powder of flat particles to be used as a raw material for soft magnetic hexagonal ferrite sintered material include, for example, both hydrothermal methods (see Publication of Japanese. Unexamined Patent Application No. 9-124322) and flux methods (see Publication of Japanese Patent No. 2717815).
However, the hydrothermal methods have a disadvantage in that it is difficult to obtain crystal particles having a relatively large size, for example, in the range of several dozen μm, by the hydrothermal methods. Another disadvantage is that the raw composite required to obtain crystal particles for use in the hydrothermal method is so expensive and so difficult to handle that industrial production of the hexagonal ferrite powder of flat particles by the methods is too costly.
On the other hand, the flux methods have a disadvantage in that it is difficult to make the crystal particles grow to a sufficient extent, although it is possible to obtain crystal particles that are larger in size than can be obtained in the hydrothermal methods. Further problems or disadvantages of the flux methods are that the flux component is prone to mixing with the other components and to appear as impurities. Also, components having poor chemistry compatibility with the flux component cannot be added to the mixtures of components.
The object of the present invention, which is to solve the above described problems, is to provide a method for producing a soft hexagonal ferrite sintered material which gives crystal particles that are larger in size than can be obtained in the methods of the prior art, and to produce a soft hexagonal ferrite sintered material which has a structure comprised of such larger crystal particles and wherein the crystal particles are oriented in a specific direction.